1. Field of the Invention
The invention relates to a method for compensating steering-torque disturbances on a motor vehicle with front-wheel drive or all-wheel drive and an active differential at the front wheels and with an active steering-servo device.
2. Description of the Related Art
When torques of unequal magnitude act on the two steerable front wheels of a motor vehicle, these are fed back into the steering system by the steering lever and produce unwanted steering-torque disturbances. In the case of a motor vehicle with front-wheel drive or all-wheel drive and a conventional differential in the drive line, the differential essentially ensures drive torques of equal magnitude at both front wheels, and the steering-torque disturbances are thus no problem. In the case of locking differentials, however, unequal distribution of the drive torque between the two front wheels may be performed deliberately in order to counteract spinning of one wheel on a slippery underlying surface. In this case, the steering-torque disturbances described above occur, and being felt in an unpleasant way by the driver.
In this context, DE 42 27 805 A1 has disclosed a control system for a locking differential in which a limiting torque may be exerted on the differential when cornering, depending on load distribution between the inner and outer wheels. Moreover, an auxiliary force is exerted by a device for active steering assistance. In this case, control is exercised in a relatively complex manner using a plurality of acceleration sensors.
Given this background, it is an object of the present invention to provide a method which, in a simple way, contributes to suppression of steering-torque disturbances produced by the action of an active differential.